Conventionally, a technology of presenting guide information as a guide for a surgeon when surgery is performed on an eye of a patient has been proposed (For example, refer to Patent Document 1). Specifically, the guide information such as a corneal range of the patient's eye and the orientation of an intraocular lens to be inserted into the eye is superimposed on an optical image or image of the intraoperative eye.
A possible method of presenting such guide information includes specifying the posture of the eye at each time during surgery, and a possible method of specifying the posture of the eye includes, for example, using a front image obtained by photographing the eye of the patient from the front.
Specifically, a possible method includes, for example, recognizing corneal and pupil ranges from preoperative and intraoperative front images, grasping a change from the preoperative position to the intraoperative position of the eye on the basis of the results of recognition, recognizing the correspondence relationship between the front images in terms of the blood vessels and iris, and thus detecting the turning angle around the eye axis of the eye as the posture of the eye. A possible method also includes presenting a wound creation position, an anterior capsule incision position, an intraocular lens orientation, and the like planned before surgery as the guide information on the basis of the turning angle or the like detected in this way.